Polyhydroxyalkanoates Production from Fruit Waste Using Bacillus Strain from Wastewater Sludge

Abstract

Polyhydroxyalkanoates (PHAs) are biodegradable polymers produced through microbial fermentation. However, the high costs associated with traditional feedstocks and fermentation techniques limit their economic feasibility. In this study, PHA-producing strains were screened from sludge samples collected at a wastewater treatment plant in Hsinchu, Taiwan. Nile red fluorescence staining and polymerase chain reaction (PCR) were used to detect the polyhydroxyalkanoate synthase (phaC) gene fragment, leading to the selection of a high-yield PHA-producing Bacillus strain for further investigation. This strain can utilize various inexpensive substrates and exhibits rapid growth, enabling efficient polyhydroxybutyrate (PHB) production without the need for sterilization or costly pretreatment processes. When fruit waste was used as the substrate, the PHB content reached 17.94%, and the PHA production yield reached 2.12 g/L. These results demonstrate the feasibility of non-sterilized fermentation using low-cost waste materials, significantly reducing the overall production costs of PHAs and providing a promising strategy for economically efficient PHB production.